http://research.microsoft.com/apps/dp/pu/publications.aspx Keep current with all the latest Microsoft Research Publications and Technical Reports © 2012 Microsoft Corporation. All rights reserved. en-US Tue, 15 May 2012 22:24:04 GMT 2880 We explore creating “cliplets”, a form of visual media that juxtaposes still image and video segments, both spatially and temporally, to expressively abstract a moment. Much as in “cinemagraphs”, the tension between static and dynamic elements in a cliplet reinforces both aspects, strongly focusing the viewer’s attention. Creating this type of imagery is challenging without professional tools and training. We develop a set of idioms, essentially spatiotemporal mappings, that characterize cliplet elements, and use these idioms in an interactive system to quickly compose a cliplet from ordinary handheld video. One difficulty is to avoid artifacts in the cliplet composition without resorting to extensive manual input. We address this with automatic alignment, looping optimization and feathering, simultaneous matting and compositing, and Laplacian blending. A key user-interface challenge is to provide affordances to define the parameters of the mappings from input time to output time while maintaining a focus on the cliplet being created. We demonstrate the creation of a variety of cliplet types. We also report on informal feedback as well as a more structured survey of users. http://research.microsoft.com/apps/pubs/default.aspx?id=164257 Tue, 15 May 2012 07:00:00 GMT Queries over large scale (petabyte) data bases often mean waiting overnight for a result to come back. Scale costs time. Such time also means that potential avenues of exploration are ignored because the costs are perceived to be too high to run or even propose them. With sampleAction we have explored whether interaction techniques to present query results running over only incremental samples can be presented as sufficiently trustworthy for analysts both to make closer to real time decisions about their queries and to be more exploratory in their questions of the data. Our work with three teams of analysts suggests that we can indeed accelerate and open up the query process with such incremental visualizations. http://research.microsoft.com/apps/pubs/default.aspx?id=163220 Sat, 05 May 2012 07:00:00 GMT Time Travel Proxy (TTP) enables participating in meetings that you cannot attend in real time, either because of time conflicts or global time zone differences. TTP uses lightweight video recordings to pre-record your contributions to a meeting, which are played on a tablet that serves as a proxy for you during the meeting. Reactions and responses in the meeting are also captured in video to give you feedback of what happened at the meeting. A working prototype of TTP was deployed and studied within four developer teams in their daily stand-up meetings. The study found that the affordances of video helped integrate the time traveler into the social context of the meeting, although the current prototype was better at enabling the time traveler to contribute to the meeting than it was in conveying the meeting experience back to the time traveler. http://research.microsoft.com/apps/pubs/default.aspx?id=163493 Sat, 05 May 2012 07:00:00 GMT People are amassing larger and more diverse collections of digital things. The emergence of Cloud computing has enabled people to move their personal files to online places, and create new digital things through online services. However, little is known about how this shift might shape people’s orientations toward their digital things. To investigate, we conducted in depth interviews with 13 people comparing and contrasting how they think about their possessions, moving from physical ones, to locally kept digital materials, to the online world. Findings are interpreted to detail design and research opportunities in this emerging space. http://research.microsoft.com/apps/pubs/default.aspx?id=158029 Sat, 05 May 2012 07:00:00 GMT Web search engines now offer more than ranked results. Queries on topics like weather, definitions, and movies may return inline results called answers that can resolve a searcher’s information need without any additional interaction. Despite the usefulness of answers, they are limited to popular needs because each answer type is manually authored. To extend the reach of answers to thousands of new information needs, we introduce Tail Answers: a large collection of direct answers that are unpopular individually, but together address a large proportion of search traffic. These answers cover long-tail needs such as the average body temperature for a dog, substitutes for molasses, and the keyboard shortcut for a right-click. We introduce a combination of search log mining and paid crowdsourcing techniques to create Tail Answers. A user study with 361 participants suggests that Tail Answers significantly improved users’ subjective ratings of search quality and their ability to solve needs without clicking through to a result. Our findings suggest that search engines can be extended to directly respond to a large new class of queries. http://research.microsoft.com/apps/pubs/default.aspx?id=157868 Sat, 05 May 2012 07:00:00 GMT This paper advocates for operating system support for personalization and describes MoRePriv, an operating system service implemented on top of the Windows Phone operating system. The approach presented in this paper combines the frequently conflicting goals of privacy and content personalization on mobile devices. We argue that personalization support should be as ubiquitous as location support, and should be provided by the OS instead of apps. To enable easy application personalization or skinning, MoRePriv approximates user's interests using personas such as technophile or business executive. We demonstrate how always-on user interest mining can effectively and accurately infer user interests in a mobile operating system by parsing and classifying multiple streams of (sensitive) information about the user within the OS, such as their email, SMS, Facebook stream, and network communications. For privacy protection, this sensitive information is distilled to a coarse-grained pro- file, without being exposed to apps, which limits the potential for information leaks. We show that MoRePriv enables simple, but effective OS-wide universal personalization: for example, long drop-down lists in application UIs are automatically sorted to better fit the order of user's likely preferences. However, the real power of MoRePriv comes from exposing a personalization API to apps. Using a number of cases studies, we illustrate how more complex personalization and app skinning tasks can be achieved with the help of MoRePriv. We also argue for better OS support for ad libraries, advocating that a more privacy-aware design is possible for mobile advertising, combined with insight into user's preferences and tastes gained with MoRePriv. This approach combines the capabilities of today's powerful ad libraries with privacy concerns of the application, while reducing application permissions and enabling more powerful monetiza- tion models. Our experiments show that we are able to reduce app permissions in about 73% of apps that use ad libraries. The ad library study also shows that removing user tracking capabilities while providing persona information creates a useful compromise in practice. http://research.microsoft.com/apps/pubs/default.aspx?id=163596 Thu, 03 May 2012 07:00:00 GMT Numerous programming languages based on process calculi have been developed for biological modelling, many of which can generate potentially unbounded numbers of molecular species and reactions. As a result, such languages cannot rely on standard reaction-based simulation methods, and are generally implemented using custom stochastic simulation algorithms. As an alternative, this paper proposes a generic abstract machine that can be instantiated to simulate a range of process calculi using a range of simulation methods. The abstract machine functions as a just-in-time compiler, which dynamically updates the set of possible reactions and chooses the next reaction in an iterative cycle. We instantiate the generic abstract machine with two Markovian simulation methods and provide encodings for four process calculi: the agent-based pi-calculus, the compartment-based bioambient calculus, the rule-based kappa calculus and the domain-specific DNA strand displacement calculus. We present a generic method for proving that the encoding of an arbitrary process calculus into the abstract machine is correct, and we use this method to prove the correctness of all four calculus encodings. Finally, we demonstrate how the generic abstract machine can be used to simulate heterogeneous models in which discrete communicating sub-models are written using different domain-specific languages and then simulated together. Our approach forms the basis of a multi-language environment for the simulation of heterogeneous biological models. http://research.microsoft.com/apps/pubs/default.aspx?id=157268 Tue, 01 May 2012 07:00:00 GMT Abstract The rational design of synthetic cell populations with prescribed behaviours is a long-standing goal of synthetic biology, with the potential to greatly accelerate the development of biotechnological applications in areas ranging from medical research to energy production. Achieving this goal requires well-characterised components, modular implementation strategies, simulation across temporal and spatial scales, and automatic compilation of high-level designs to low-level genetic parts that function reliably inside cells. Many of these steps are incomplete or only partially understood, and methods for integrating them within a common design framework have yet to be developed. Here we address these challenges by developing a prototype framework for designing synthetic cells with prescribed population dynamics. We extend the GEC language, originally developed for programming intra-cellular dynamics, with cell population factors such as cell growth, division and dormancy, together with spatio-temporal simulation methods. As a case study, we use our framework to design synthetic cells with predator-prey interactions that, when simulated, produce complex spatiotemporal behaviours such as travelling waves and spatiotemporal chaos. Analysis of our design reveals that environmental factors such as density-dependent dormancy and reduced extracellular space destabilise the population dynamics and increase the range of genetic variants for which complex spatiotemporal behaviours are possible. Our findings highlight the importance of considering such factors during the design process. We then use our analysis of population dynamics to inform the selection of genetic parts, which could be used to obtain the desired spatiotemporal behaviours. By identifying, integrating and automating key stages of the design process, we provide a computational framework for designing synthetic systems that could be tested in future laboratory studies. We then use our analysis of population dynamics to inform the selection of genetic parts, which could be used to obtain the desired spatiotemporal behaviours. By identifying, integrating and automating key stages of the design process, we provide a computational framework for designing synthetic systems that could be tested in future laboratory studies. http://research.microsoft.com/apps/pubs/default.aspx?id=164192 Tue, 01 May 2012 07:00:00 GMT Parallelization of unit propagation in SAT solvers is a compelling way of obtaining an efficient parallel decision procedure for the propositional satisfiability problem. However, due to the P-completeness of unit propagation, it is challenging to achieve good efficiency in practice. In this article, we present two methods for unit propagation on multi-core systems and their implementation. We throughly evaluate these techniques by comparison to a simulation that estimates a baseline efficiency and by experimental evaluation of an implementation on competition benchmarks. We thereby demonstrate that achieving a speed-up linear in the number of cores is indeed challenging in practice, but also that unit propagation on multi-core systems is feasible in practice. http://research.microsoft.com/apps/pubs/default.aspx?id=163505 Tue, 01 May 2012 07:00:00 GMT http://research.microsoft.com/apps/pubs/default.aspx?id=163718 Tue, 01 May 2012 07:00:00 GMT http://research.microsoft.com/apps/pubs/default.aspx?id=163714 Tue, 01 May 2012 07:00:00 GMT A heterogeneous multicore processor has several cores that share the same instruction set architecture but run at different speeds and power consumption rates, offering both energy efficient cores and high-performance cores to applications. We show how to exploit such processors to make significant energy reduction to serve large interactive workloads such as web search by carefully scheduling requests. Scheduling is a challenging task. Intuitively, we want to run short requests on slow cores for energy efficiency and long requests on fast cores for timely responses. However, there are two key challenges: (1) request service demands are unknown; and (2) the most appropriate core to run a request may be busy. We propose an online algorithm, Fast-Preempt-Slow (FPS), which improves response quality subject to deadline and total power constraints. We conduct a simulation study using measured workload from a large commercial web search engine as well as using a variety of synthetic workloads to assess the benefits of FPS. Our results show significant benefits, achievable under a wide variety of conditions: The throughput of a heterogeneous processor is 60% higher than that of the corresponding homogeneous processor with the same power budget; equivalently, to support a large workload as in Web search, FPS on the heterogeneous processors reduces the number of servers by approximately 40%. http://research.microsoft.com/apps/pubs/default.aspx?id=163592 Tue, 01 May 2012 07:00:00 GMT This is a tutorial on location-based social networks (LBSNs), introducing the concept, unique features, and research philosophy of LBSNs and the representative research into LBSNs. The homepage of LBSN is http://research.microsoft.com/en-us/projects/lbsn/default.aspx. http://research.microsoft.com/apps/pubs/default.aspx?id=163521 Tue, 01 May 2012 07:00:00 GMT http://research.microsoft.com/apps/pubs/default.aspx?id=163593 Tue, 01 May 2012 07:00:00 GMT http://research.microsoft.com/apps/pubs/default.aspx?id=163517 Tue, 01 May 2012 07:00:00 GMT We are facing challenges at all levels ranging from infrastructures to programming models for managing and mining large graphs. A lot of algorithms on graphs are ad-hoc in the sense that each of them assumes that the underlying graph data can be organized in a certain way that maximizes the performance of the algorithm. In other words, there is no standard graph systems based on which graph algorithms are developed and optimized. In response to this situation, a lot of graph systems have been proposed recently. In this tutorial, we discuss several representative systems. Still, we focus on providing perspectives from a variety of standpoints on the goals and the means for developing a general purpose graph system. We highlight the challenges posed by the graph data, the constraints of architectural design, the different types of application needs, and the power of different programming models that support such needs. http://research.microsoft.com/apps/pubs/default.aspx?id=161926 Tue, 01 May 2012 07:00:00 GMT Query substitution is an important problem in information retrieval. Much work focuses on how to find substitutes for any given query. In this paper, we study how to efficiently process a keyword query whose substitutes are defined by a given taxonomy. This problem is challenging because each term in a query can have a large number of substitutes, and the original query can be rewritten into any of their combinations. We propose to build an additional index (besides inverted index) to efficiently process queries. For a query workload, we formulate an optimization problem which chooses the additional index structure, aiming at minimizing the query evaluation cost, under given index space constraints. We show the NP-hardness of the problem, and propose a pseudo-polynomial time algorithm using dynamic programming, as well as an 1/4*(1−1/e)-approximation algorithm to solve the problem. Experimental results show that, with only 10% additional index space, our approach can greatly reduce the query evaluation cost. http://research.microsoft.com/apps/pubs/default.aspx?id=158738 Tue, 01 May 2012 07:00:00 GMT Knowledge is indispensable to understanding. The ongoing information explosion highlights the need to enable machines to better understand electronic text in human language. Much work has been devoted to creating universal ontologies or taxonomies for this purpose. However, none of the existing ontologies has the needed depth and breadth for “universal understanding”. In this paper, we present a universal, probabilistic taxonomy that is more comprehensive than any existing ones. It contains 2.7 million concepts harnessed automatically from a corpus of 1.68 billion web pages. Unlike traditional taxonomies that treat knowledge as black and white, it uses probabilities to model inconsistent, ambiguous and uncertain information it contains. We present details of how the taxonomy is constructed, its probabilistic modeling, and its potential applications in text understanding. http://research.microsoft.com/apps/pubs/default.aspx?id=158737 Tue, 01 May 2012 07:00:00 GMT With the boom of software-as-a-service and social networking, web-based single sign-on (SSO) schemes are being deployed by more and more commercial websites to safeguard many web resources. Despite prior research in formal verification, little has been done to analyze the security quality of SSO schemes that are commercially deployed in the real world. Such an analysis faces unique technical challenges, including lack of access to well-documented protocols and code, and the complexity brought in by the rich browser elements (script, Flash, etc.). In this paper, we report the first “field study” on popular web SSO systems. In every studied case, we focused on the actual web traffic going through the browser, and used an algorithm to recover important semantic information and identify potential exploit opportunities. Such opportunities guided us to the discoveries of real flaws. In this study, we discovered 8 serious logic flaws in high-profile ID providers and relying party websites, such as OpenID (including Google ID and PayPal Access), Facebook, JanRain, Freelancer, FarmVille, Sears.com, etc. Every flaw allows an attacker to sign in as the victim user. We reported our findings to affected companies, and received their acknowledgements in various ways. All the reported flaws, except those discovered very recently, have been fixed. This study shows that the overall security quality of SSO deployments seems worrisome. We hope that the SSO community conducts a study similar to ours, but in a larger scale, to better understand to what extent SSO is insecurely deployed and how to respond to the situation. http://research.microsoft.com/apps/pubs/default.aspx?id=160659 Tue, 01 May 2012 07:00:00 GMT http://research.microsoft.com/apps/pubs/default.aspx?id=159486 Tue, 01 May 2012 07:00:00 GMT